In Vivo Bioconcentration of 10 Anionic Surfactants in Rainbow Trout Explained by In Vitro Data on Partitioning and S9 Clearance

Bioconcentration factors (BCFs) in rainbow troutwere measured for 10 anionic surfactants with a range of alkylchain lengths and different polar head groups. The BCFs rangedfrom 0.04 L kg-1ww (for C10SO3) to 1370 L kg-1ww (C16SO3).There was a strong correlation between the log BCF and logmembrane lipid-water distribution ratio (DMLW,r2= 0.96), andbiotransformation was identified as the dominant eliminationmechanism. The strong positive influence ofDMLWon BCF wasattributed to two phenomena: (i) increased partitioning from waterinto the epithelial membrane of the gill, leading to more rapiddiffusion across this barrier and more rapid uptake, and (ii)increased sequestration of the surfactant body burden intomembranes and other body tissues, resulting in lower freelydissolved concentrations available for biotransformation. Estimated whole-bodyin vivobiotransformation rate constantskB???BCFarewithin a factor three of rate constants estimated from S9in vitroassays for six of the eight test chemicals for whichkB???BCFcould bedetermined. A model-based assessment indicated that the hepatic clearance rate of freely dissolved chemicals was similar for thestudied surfactants. The dataset will be useful for evaluation ofin silicoandin vitromethods to assess bioaccumulation